(1) Field of the Invention
The present invention relates to image forming apparatuses and methods of an electrophotograph type that are capable of forming color images.
(2) Description of the Related Art
It has been a trend in the particular technical field of color image forming apparatuses to develop facsimiles, printers and the like capable of forming color images by means of subtractive color mixing, using four or more color toners including the three primaries of cyan, magenta, and yellow on top of the key color black (also known as CMYK) (“Electrophotography—Bases and Applications II,” edited by the Society of Electrophotography of Japan, published by Corona Publishing Co. Ltd., Nov. 15, 1996, pp 31, 55).
By the four-color process printing with the general CMYK color toners, as in most of the commercial applications, reproduction of an image or text in color produces a final result precisely faithful to the original. When it comes to charts or graphs, faithful reproduction of original colors is not required in many occasions, and for users considering the color reproducibility to be less important, it is preferable to achieve costs-savings by suppressing the toner consumption. However, there is no image forming apparatuses at present that satisfy such users' needs.